scholarly journals Label-Free Electrochemical Test of Protease Interaction with a Peptide Substrate Modified Gold Electrode

Chemosensors ◽  
2021 ◽  
Vol 9 (8) ◽  
pp. 199
Author(s):  
Anna Wcisło ◽  
Izabela Małuch ◽  
Paweł Niedziałkowski ◽  
Tadeusz Ossowski ◽  
Adam Prahl
Keyword(s):  
Gold Electrode ◽  
High Selectivity ◽  
Electrode Materials ◽  
Electrochemical Biosensors ◽  
Electrochemical Characteristics ◽  
Label Free ◽  
Peptide Substrate ◽  
Electrochemical Test ◽  
Experimental Conditions ◽  
Spectrofluorimetric Method

Efficient deposition of biomolecules on the surface, maintaining their full activity and stability, is a most significant factor in biosensor construction. For this reason, more and more research is focused on the development of electrochemical biosensors that have the ability to electrically detect adsorbed molecules on electrode surface with high selectivity and sensitivity. The presented research aims to develop an efficient methodology that allows quantification of processes related to the evaluation of enzyme activity (proprotein convertase) using electrochemical methods. In this study we used impedance spectroscopy to investigate the immobilization of peptide substrate (Arg-Val-Arg-Arg) modified with 11-mercaptoundecanoic acid on the surface of gold electrode. Both the synthesis of the peptide substrate as well as the full electrochemical characteristics of the obtained electrode materials have been described. Experimental conditions, including concentration of peptide substrate immobilization, modification time, linker, and the presence of additional blocking groups have been optimized. The main advantages of the described method is that it makes it possible to observe the peptide substrate–enzyme interaction without the need to use fluorescent labels. This also allows observation of this interaction at a very low concentration. Both of these factors make this new technique competitive with the standard spectrofluorimetric method.

Comparison of Gold and Platinum Electrode Responses in Activated Sludge

1993 ◽  
Vol 28 (11-12) ◽  
pp. 473-480
Author(s):  
A. Heduit ◽  
B. Martin ◽  
I. Duchamp ◽  
D. R. Thevenot
Keyword(s):  
Electron Transfer ◽  
Activated Sludge ◽  
Gold Electrode ◽  
Platinum Electrode ◽  
Electrochemical Determination ◽  
Exchange Current ◽  
Experimental Conditions ◽  
Equilibrium Exchange ◽  
Prolonged Contact ◽  
Current Densities

Gold and platinum were compared to ascertain how they expressed a stabilized potential in activated sludge. The comparison was based on electrochemical determination of the electron transfer rate (i.e. equilibrium exchange current density) and recording of potentials against time. When both metals are treated in the same way, platinum gives equilibrium exchange current densities approx. 10 times higher than gold, both in aerated activated sludge and in treated water. For platinum, the equilibrium exchange current densities range from 0.1 to 0.25 µA/cm2 immediately after polishing and decrease during prolonged contact with activated sludge subjected to alternating aeration/anoxia sequences. The lower kinetics of electron transfer on gold go together with significant differences in response:- In an aerobic medium a gold electrode potential is lower than that of a platinum electrode. In a strongly anaerobic medium, the reverse is true. Consequently, the amplitude of the potential variation between aerobic and anaerobic media is smaller for gold than for platinum. Under our experimental conditions this amplitude was approx 350 mV for gold and 850 mV for platinum.- The slopes of the linear relationships between potential and pH or potential and the logarithm of the dissolved oxygen concentration are two or three times greater for platinum than for gold. Although the values obtained with platinum electrodes cannot represent a veritable equilibrium state, the platinum electrode zero-current potential would seem to be far more sensitive to variations in the medium than that of the gold electrode; it is, therefore, more suitable for use in activated sludge.

Electrochemical Characteristics of Aptasensor Based on MEMS Thin-Film Gold Electrode

2013 ◽  
Vol 562-565 ◽  
pp. 441-445
Author(s):  
Yan Xia Yan ◽  
Li Ying Jiang ◽  
Fen Fen Wang ◽  
Yan Zhang ◽  
Jie Hu
Keyword(s):  
Thin Film ◽  
Self Assembly ◽  
Gold Electrode ◽  
Ac Impedance ◽  
Optimum Concentration ◽  
Electrochemical Characteristics ◽  
Universal Method

A new fabrication methods of thin-film gold electrode is reported. Electrochemical characteristics of self-assembly aptasensor based on MEMS thin-film gold electrode has been studied by lots of experiments, characteristics include immobilizing time, AC impedance, CV curves. Experiments indicate immobilizing time of DNA-SH on gold electrode is more than 15 hours. CV curves and AC impedance of MEMS thin-film gold electrode show the same conclusion that 20μm/L DNA is optimum concentration when DNA is immobilized on gold electrode. Those results present a potential universal method for other aptasensors.

Carbon nanotubes as electrode materials for the assembling of new electrochemical biosensors

2004 ◽  
Vol 100 (1-2) ◽  
pp. 117-125 ◽  
Author(s):  
Federica Valentini ◽  
Silvia Orlanducci ◽  
Maria Letizia Terranova ◽  
Aziz Amine ◽  
Giuseppe Palleschi
Keyword(s):  
Carbon Nanotubes ◽  
Electrode Materials ◽  
Electrochemical Biosensors

scholarly journals Label-free cell based impedance measurements of ZnO nanoparticles—human lung cell interaction: a comparison with MTT, NR, Trypan blue and cloning efficiency assays

2021 ◽  
Vol 19 (1) ◽  
Author(s):  
Giuseppina Bozzuto ◽  
Giuseppe D’Avenio ◽  
Maria Condello ◽  
Simona Sennato ◽  
Ezio Battaglione ◽  
...  
Keyword(s):  
Trypan Blue ◽  
A549 Cells ◽  
Cell Interaction ◽  
Neutral Red ◽  
Free Cell ◽  
Mitogenic Activity ◽  
Label Free ◽  
Cloning Efficiency ◽  
Zno Nps ◽  
Experimental Conditions

Abstract Background There is a huge body of literature data on ZnOnanoparticles (ZnO NPs) toxicity. However, the reported results are seen to be increasingly discrepant, and deep comprehension of the ZnO NPs behaviour in relation to the different experimental conditions is still lacking. A recent literature overview emphasizes the screening of the ZnO NPs toxicity with more than one assay, checking the experimental reproducibility also versus time, which is a key factor for the robustness of the results. In this paper we compared high-throughput real-time measurements through Electric Cell-substrate Impedance-Sensing (ECIS®) with endpoint measurements of multiple independent assays. Results ECIS-measurements were compared with traditional cytotoxicity tests such as MTT, Neutral red, Trypan blue, and cloning efficiency assays. ECIS could follow the cell behavior continuously and noninvasively for days, so that certain long-term characteristics of cell proliferation under treatment with ZnO NPs were accessible. This was particularly important in the case of pro-mitogenic activity exerted by low-dose ZnO NPs, an effect not revealed by endpoint independent assays. This result opens new worrisome questions about the potential mitogenic activity exerted by ZnO NPs, or more generally by NPs, on transformed cells. Of importance, impedance curve trends (morphology) allowed to discriminate between different cell death mechanisms (apoptosis vs autophagy) in the absence of specific reagents, as confirmed by cell structural and functional studies by high-resolution microscopy. This could be advantageous in terms of costs and time spent. ZnO NPs-exposed A549 cells showed an unusual pattern of actin and tubulin distribution which might trigger mitotic aberrations leading to genomic instability. Conclusions ZnO NPs toxicity can be determined not only by the intrinsic NPs characteristics, but also by the external conditions like the experimental setting, and this could account for discrepant data from different assays. ECIS has the potential to recapitulate the needs required in the evaluation of nanomaterials by contributing to the reliability of cytotoxicity tests. Moreover, it can overcome some false results and discrepancies in the results obtained by endpoint measurements. Finally, we strongly recommend the comparison of cytotoxicity tests (ECIS, MTT, Trypan Blue, Cloning efficiency) with the ultrastructural cell pathology studies. Graphic Abstract

scholarly journals Electrochemical hydrogenation, lithiation and sodiation of the GdFe2–xMx and GdMn2–xMx intermetallics

2021 ◽  
pp. 139-149
Keyword(s):  
Electrode Materials ◽  
Electrochemical Impedance ◽  
Diffraction Method ◽  
Electrochemical Characteristics ◽  
Electrochemical Hydrogenation ◽  
Hydrogen Atoms ◽  
X Ray ◽  
Cell Parameters ◽  
The Difference ◽  
Better Than

Electrochemical hydrogenation, lithiation and sodiation of the phases GdFe2–xMx and GdMn2–xMx (M=Mn, Co, Ni, Zn, and Mg) and the influence of doping components on electrochemical characteristics of electrode materials on their basis were studied using X-ray powder diffraction method, scanning electron microscopy, energy dispersive X-ray analysis, X-ray fluorescent spectroscopy, cyclic voltammetry and electrochemical impedance spectroscopy. Phase analysis showed a simple correspondence between unit cell parameters of the phases and atomic radii of doping elements. Electrode materials based on GdFe2 and GdMn2 doped with 2 at.% of Co, Ni and Mg demonstrated better hydrogen sorption properties than those doped with Mn and Zn. Corrosion resistance of the doped electrodes was also better than of the binary analogues (e.g. corrosion potential of the GdFe2-based electrode was –0.162 V whereas that of GdFe1.96Ni0.04 was –0.695 V). The capacity parameters were increased in the following ranges: Zn<Mn<Mg<Co<Ni and Zn<Fe<Mg<Co<Ni for GdFe2–xMx and GdMn2–xMx, respectively. After fifty cycles of charge/discharge, we observed the changes in surface morphology and composition of the electrode samples. In the structure of studied Laves type phases with MgCu2-type structure, the most suitable sites for hydrogen atoms are tetrahedral voids 8a. During lithiation and sodiation of the phases, the atoms of the M-component of the structure are replaced by the atoms of lithium, and the atoms of gadolinium are replaced by the atoms of sodium. This difference in interaction is due to the difference in atomic sizes of the atoms. No insertion of lithium or sodium into the structural voids of the phases was observed.

scholarly journals Research on Key Technology of Electrochemical Sterilization and Physical Application for Circulating Cooling Water

2021 ◽  
Vol 2083 (2) ◽  
pp. 022068
Author(s):  
Xiaohui Wang ◽  
Chunyan Song ◽  
Xueying Xie ◽  
Nan Zhang ◽  
Ruiqing Guo ◽  
...  
Keyword(s):  
Electric Fields ◽  
Electrode Materials ◽  
High Efficiency ◽  
Thermal Power ◽  
Cooling Water ◽  
Environmentally Friendly ◽  
Research Progress ◽  
Electrode Spacing ◽  
Experimental Conditions ◽  
Circulating Cooling Water

Abstract As a high-efficiency, low-cost, convenient and environmentally friendly sterilization technology, electrochemical disinfection has developed rapidly in recent years. Electrochemical sterilization is an environmentally friendly sterilization technology. The research progress of this technology in the recent 30 years in sterilization mechanism and electrode materials is summarized. The mechanism of electrochemical sterilization includes the chemical effects of active chlorine, active intermediates, copper or silver ions, and the physical effects of electric fields; the electrode materials used are titanium anode, carbon cathode, and anode. The article combined with electrochemical equipment in a thermal power plant cold open circulating cooling water treatment experiment. Experimental research found that under the conditions of current density of 120A/m2, residence time of 10s, and electrode spacing of 1.8cm, the bactericidal effect can reach 97%. Under certain experimental conditions and a certain period of time, the total number of heterogeneous bacteria in the circulating cooling water after treatment can be effectively inhibited.

scholarly journals Label-Free Electrochemical Biosensors for the Determination of Flaviviruses: Dengue, Zika, and Japanese Encephalitis

Sensors ◽  
2020 ◽  
Vol 20 (16) ◽  
pp. 4600 ◽  
Author(s):  
Ekaterina Khristunova ◽  
Elena Dorozhko ◽  
Elena Korotkova ◽  
Bohumil Kratochvil ◽  
Vlastimil Vyskocil ◽  
...  
Keyword(s):  
Japanese Encephalitis ◽  
Electrode Materials ◽  
Biological Fluids ◽  
Research Progress ◽  
Immunological Methods ◽  
Label Free ◽  
Viral Pathogens ◽  
Electrochemical Biosensing ◽  
Wide Range

A highly effective way to improve prognosis of viral infectious diseases and to determine the outcome of infection is early, fast, simple, and efficient diagnosis of viral pathogens in biological fluids. Among a wide range of viral pathogens, Flaviviruses attract a special attention. Flavivirus genus includes more than 70 viruses, the most familiar being dengue virus (DENV), Zika virus (ZIKV), and Japanese encephalitis virus (JEV). Haemorrhagic and encephalitis diseases are the most common severe consequences of flaviviral infection. Currently, increasing attention is being paid to the development of electrochemical immunological methods for the determination of Flaviviruses. This review critically compares and evaluates recent research progress in electrochemical biosensing of DENV, ZIKV, and JEV without labelling. Specific attention is paid to comparison of detection strategies, electrode materials, and analytical characteristics. The potential of so far developed biosensors is discussed together with an outlook for further development in this field.

scholarly journals Immune cell type, cell activation, and single cell heterogeneity revealed by label-free optical methods

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Nicolas Pavillon ◽  
Nicholas I. Smith
Keyword(s):  
Single Cell ◽  
Cell Activation ◽  
Immune Cell ◽  
Global Analysis ◽  
Measurement Techniques ◽  
Optical Methods ◽  
Phase Imaging ◽  
Label Free ◽  
Experimental Conditions ◽  
Culturing Conditions

AbstractMeasurement techniques that allow the global analysis of cellular responses while retaining single-cell sensitivity are increasingly needed in order to understand complex and dynamic biological processes. In this context, compromises between sensitivity, degree of multiplexing, throughput, and invasiveness are often unavoidable. We present here a noninvasive optical approach that can retrieve quantitative biomarkers of both morphological and molecular phenotypes of individual cells, based on a combination of quantitative phase imaging and Raman spectroscopy measurements. We then develop generalized statistical tools to assess the influence of both controlled (cell sub-populations, immune stimulation) and uncontrolled (culturing conditions, animal variations, etc.) experimental parameters on the label-free biomarkers. These indicators can detect different macrophage cell sub-populations originating from different progenitors as well as their activation state, and how these changes are related to specific differences in morphology and molecular content. The molecular indicators also display further sensitivity that allow identification of other experimental conditions, such as differences between cells originating from different animals, allowing the detection of outlier behaviour from given cell sub-populations.

Anodic Voltammetric Behavior of Lincomycin and its Electroanalytical Determination in Pharmaceutical Dosage form and Urine at Gold Electrode

2017 ◽  
Vol 231 (5) ◽  
Author(s):  
Jyothi C. Abbar ◽  
Manjunath D. Meti ◽  
Sharanappa T. Nandibewoor
Keyword(s):  
Gold Electrode ◽  
Dosage Form ◽  
Oxidation Process ◽  
Linear Sweep Voltammetry ◽  
Linear Sweep ◽  
Experimental Conditions ◽  
Pharmaceutical Dosage Form ◽  
Antibiotic Drug ◽  
Voltammetric Behavior

AbstractThe anodic voltammetric behavior of an antibiotic drug, lincomycin hydrochloride (LIN) at gold electrode (GE) has been investigated using cyclic and linear sweep voltammetry. The dependence of the current on pH, concentration and scan rate were investigated to optimize the experimental conditions for the determination of lincomycin. The anodic peak was characterized and the process was adsorption-controlled. The number of electrons transferred in the oxidation process was calculated. In the range of 8.0×10

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